Spatiotemporally Controllable Chemical Delivery Utilizing Electroosmotic Flow Generated in Combination of Anionic and Cationic Hydrogels

Spatiotemporally controlled chemical delivery is crucial for various biomedical engineering applications. Here, a novel concept of electrically controllable delivery utilizing electroosmotic flow (EOF) generated in a combination of anionic and cationic hydrogels (A- and C-hydrogels) is reported. The unique advantages of the A/C-hydrogel combination are demonstrated utilizing a flexible sheet-shaped and a thin tubular devices. Since the directions of EOF in the A- and C-hydrogels are opposite to each other, the ionic current for EOF generation flows inside the delivery devices, enabling chemical delivery without accompanying external ionic current that could stimulate target cells and tissues. A thin tubular device, which can be inserted into narrow in vivo structures and be integrated with other flexible devices, exhibits high robustness and repeatability thanks to the flexibility and water retentivity of hydrogels. The EOF devices with A/C-hydrogels combination show high controllability superior to the pumping with a conventional syringe; the volumetric flow rate is able to be controlled proportionally to the current applied, for example, ≈0.4 µL (mA min)⁻¹ for the tubular device. The developed EOF-based devices are versatile for delivery of most chemicals regardless of their charge and size, and have great potential for both biomedical researches and therapeutics.     

Analysis of thermal radiation,Joule heating,and viscous dissipation effects on blood-gold couple stress nanofluid flow driven by electroosmosis

Gold nanoparticles associated with DNA, RNA, proteins, oligonucleotides, and peptides are useful in therapies and drug delivery. The present article mainatins that gold nanoparticles play a tremendous role in remedying cancer and fatal diseases. A mathematical model is proposed for the two-dimensional motion of the couple stress nanofluid consisting of gold nanoparticles under the application of peristaltic propulsion and electroosmosis mechanisms in an asymmetric microchannel. The effects of radiation with slip boundary have been employed. The governing equations are simplified under the assumptions of low Reynolds number and long wavelength and the Poisson-Boltzmann equation is solved under Debye–Hückel linearization. Analytical solutions for the velocity of fluid motion, nanoparticle temperature, stream function, pressure gradient, are evaluated and analyzed graphically under the effects of various physical parameters. It is notable from the analysis that raising the Brinkman number boosts the nanoparticle temperature and heat transfer coefficient which validate the physical model and analysis. Moreover, it is noticed that sphere-shaped gold nanoparticles enhance the temperature as compared to other geometries of nanoparticles. The present study results may assist in developing the technology, smart micropumps, drugs, and device for hemodialysis and other health care applications.     

古木硅化处理对其物化性能的影响

在田螺山遗址的挖掘过程中,出土了大量的木质文物。由于年代久远且长期处于潮湿环境,木质文物现已出现腐朽、开裂等问题,濒临毁灭。为对这些古木实施保护,我们受自然界硅化木的启发,将这些古木进行硅化处理。为在较短时间内实现长期有效的原位硅化加固目的,我们采用电渗法先对古木进行加速硅化处理,再进行钙化处理。在电子显微镜下可见,经处理后的古木内部由层片状硅酸钙大量填充,而表面则被细致的硅酸钙颗粒完整覆盖。在宏观性能上,经处理后古木抗压性能提升了150%左右,保水性能亦大幅提升,不易失水干缩,这种硅化处理对古木起到了强化保护作用。     

混合电源输出方式下的一维电渗试验研究

利用改进的一维电渗固结试验装置对饱和软黏土进行电渗试验,通过监测电渗过程中的电流、电压、电势、排水量、电渗前后的含水率和抗剪强度,利用电渗透系数、电迁移系数、能耗系数来研究不同电源输出方式下的电渗排水状况。试验结果表明:相比于稳压输出方式,压流模式下的累积排水量更小且排水速率更慢,有效电势利用率变化幅度略小,电渗透系数和电迁移系数衰减得更快,含水率的总下降值和归一化抗剪强度略大;相比于稳流输出方式,流压模式下的累积排水量更大且排水速率更快,有效电势利用率变化幅度更小,电渗透系数和电迁移系数衰减得更慢,含水率总下降值和归一化抗剪强度更大。通过对不同电源输出方式下能耗系数递增速度的对比,得出流压模式下电渗工况更经济合理。     

无机离子的高效毛细管电泳分析

本文对无机离子的高效毛细管电泳分析技术进行了综述与分析，包括毛细管的内壁处理、缓冲液的组成及各种检测方法，并展望了其发展前景。本文引用文献８１篇。     

ELECTROKINETIC DEWATERING OF BALL CLAY

A cell for the electrokinetic dewatering of ball clay is described. By combining the electroosmotic and electrophoretic processes it has been demonstrated that the electrokinetic cell can be operated on a continuous basis. The electroosmotic and electrophoretic processes are found to be directly proportional to the applied current as predicted by electrokinetic theory. Ball clay was found to deposit in the range 60-70% solids with an accompanying energy requirement of 100-170Wh/Kg, based on a dry weight basis. The corresponding deposition rate was 50kg/m2/hr at a current density of 145/m2. The parallel electroosmotic water removal process was found to occur at a rate of 120dm3/hr/m2 for a specific energy consumption of 55Wh/dm3.     

交流电沉积实现微纳器件定向连接研究

使用交流电化学方法定向制备了预制微电极之间的电连接。通过调节交流电压与偏置直流电压幅值可以控制电连接的生长方向。如果施加的交流电压幅值高于生成电连接的电压阈值,并且该值恒定时,频率越小,浓度越大,电连接晶体越粗壮;而当电解液浓度与频率恒定时,电压幅值变化对形貌影响较小。有限元仿真模拟进一步说明：当施加的交流电压高于阈值时,电极处于交流电渗流上游。电极扩散层厚度增加将诱导电极之间电连接晶体的生长。在交流电压上叠加直流偏置电压时,电连接晶体从偏置电压相对较负的一端向另一端生长。伏安特性测试结果表明：该连接具有优异的接触特性。     

焦耳热效应对毛细管电泳中样品区带传输的影响

毛细管区带电泳过程中产生焦耳热效应会改变溶液的黏度,进而改变样品区带到达检测窗口的时间。建立了一个包含电势分布方程、连续性方程、动量方程、能量方程和样品组分迁移扩散方程的数学模型,应用有限元数值模拟的方法,对这些耦合的方程进行了求解。计算结构分析了在考虑和不考虑焦耳热的情况下样品组分区带的传输过程。结果表明,毛细管内径、对流换热系数及缓冲溶液浓度都会影响样品区带在毛细管中的运动速度,进而改变其到达检测窗口的时间。     

电渗滤水混凝土的应用研究

目的通过将电渗技术引入到混凝土施工过程，解决混凝土工程中施工要求的大水灰质量比与使用性能要求的小水灰质量比之间的矛盾问题．方法采用电渗技术，利用水泥水化产生的双电层的导电性能。使混凝土中的多余水分向阴极聚集。以减少混凝土的凝结水灰质量比．结果实验表明电渗技术可以显著提高滤水混凝土的滤水速度，明显提高混凝土的强度，并有很好的经济性．结论电渗滤水混凝土技术能有效地解决混凝土的大水灰质量比施工、小水灰质量比固化的矛盾，有重要学术价值和广阔的应用前号．     

电渗过程中电极与土体间电荷积累问题研究

电渗过程中的电荷积累现象是电极和土体界面间存在电压降的主要原因,将电荷积累区域视为一特殊电容器,模拟了土与电极界面间的电容效应,推导了界面电容与土体电阻串联后土体中的电压降、电容间距和孔隙水压力,通过圆柱形电极和电极板试验,验证了界面电容假设的合理性,同时指出随着电渗的进行,电荷积累增多,电压降增大,且圆柱形电极形成的电容大于电极板形成的电容。